JP5515791B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that also performs cylinder deactivation operation for deactivating a cylinder.

  Some internal combustion engines perform fuel cut to stop fuel injection when the vehicle is decelerated. By performing fuel cut in this way, fuel consumption can be suppressed and fuel consumption can be improved. In addition, a catalyst device made of a catalyst such as a three-way catalyst is provided in the exhaust passage of the internal combustion engine in order to purify harmful components (for example, HC, CO, NOx) contained in the exhaust gas.

  When the fuel cut is performed, since the fuel is not burned, the sucked oxygen is not consumed, a large amount of oxygen (fresh air) is exhausted, and oxygen flows into the catalyst. Thus, it is known that when the catalyst is in an oxygen-excess state, deterioration of the catalyst is promoted. Therefore, as a method of suppressing such deterioration of the catalyst, for example, when the fuel is cut, the intake / exhaust valve is stopped (cylinder deactivation) so that oxygen is not exhausted and oxygen is prevented from flowing into the catalyst. (See Patent Document 1).

JP 2004-143990 A JP-A-7-103031 JP 2000-146011 A

  When the valve is stopped, a solenoid is used to keep the valve fully closed. The solenoid opens and closes the valve according to the energized state from the battery. When the battery voltage fluctuates, the rise (responsiveness) of the current supplied to the solenoid also changes, and when the battery voltage decreases, the rise of the solenoid current is delayed. Therefore, when the battery voltage decreases, the time until the holding current necessary for maintaining the fully closed state of the valve is supplied compared to the case where the battery voltage is normal (12 V) (and the operation of the movable part of the solenoid). The time until the valve is fully closed after completion of is increased. As a result, even when the fuel cut control is executed after the fuel cut request and the fuel injection is stopped, the valve stop is not completed even if the valve stop control is executed after the valve stop request. While this valve stop completion is delayed, oxygen is exhausted, oxygen flows into the catalyst, and the catalyst deteriorates.

  Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that suppresses catalyst deterioration during cylinder deactivation operation of the internal combustion engine.

The control device for an internal combustion engine according to the present invention is a control device for an internal combustion engine that also performs cylinder deactivation operation for deactivating a cylinder when a specific condition is satisfied, and controls the fuel injection for each cylinder, and the specific condition The fuel injection control means for stopping the fuel injection when the condition is established and the opening and closing of the intake valve and the exhaust valve for each cylinder are controlled, and when the specific condition is established, the intake valve and / or the exhaust valve is closed. A valve control means for holding control and a battery voltage detection means for detecting the voltage of the battery are provided. The valve control means controls the opening and closing of the intake valve and the exhaust valve for each cylinder by each solenoid according to the energized state from the battery. and, respectively retain control in the closed state by the solenoids, fuel injection control means, when the voltage of the battery a specific condition is detected by the battery voltage detection means when established threshold below the fuel injection And wherein the delaying the timing to stop.

  In this control device for an internal combustion engine, when a specific condition for performing the cylinder deactivation operation is satisfied and the battery voltage detected by the battery voltage detection means is normal, the fuel injection control means immediately controls to stop fuel injection. At the same time, the valve control means controls to keep the intake valve and / or the exhaust valve closed. However, in this control device, when a specific condition for performing the cylinder deactivation operation is satisfied and the battery voltage detected by the battery voltage detection means is equal to or lower than the threshold value, the valve control means immediately closes the intake valve and / or the exhaust valve. The control for maintaining the state is performed, but the control for delaying the fuel injection timing by the fuel injection control means is performed as compared with the case where the battery voltage is normal. In this case, the timing at which the fuel injection is stopped is delayed after the control to maintain the closed state of the intake valve and / or the exhaust valve due to a decrease in the battery voltage until the battery voltage is normal until the valve is closed. Therefore, oxygen is consumed by combustion by the injected fuel during the delay, and oxygen does not flow to the catalyst. As described above, in this control device for an internal combustion engine, when the battery voltage is reduced during the cylinder deactivation operation, the deterioration of the catalyst can be suppressed by delaying the timing of stopping the fuel injection.

  In the control apparatus for an internal combustion engine according to the present invention, the fuel injection control means increases the difference between the threshold value and the battery voltage when the battery voltage detected by the battery voltage detection means is less than or equal to the threshold value when a specific condition is satisfied. It is preferable to delay the timing for stopping the fuel injection.

  The greater the degree of decrease in battery voltage, the longer it takes to start the control to maintain the closed state of the intake valve and / or the exhaust valve until the valve is closed. Therefore, in this control apparatus for an internal combustion engine, when a specific condition for performing cylinder deactivation operation is satisfied and the battery voltage is equal to or lower than the threshold value, the difference between the threshold value and the battery voltage by the fuel injection control means increases (that is, normal Control is performed to further delay the timing of stopping fuel injection (as the difference between the battery voltage and the lowered battery voltage increases). As described above, in this control device for an internal combustion engine, the timing at which the intake valve and / or the exhaust valve are closed is increased by delaying the timing at which the fuel injection is stopped as the difference between the threshold value and the battery voltage increases. The timing for stopping the gas can be matched as much as possible, and oxygen can be prevented from flowing into the catalyst as much as possible.

  In the control apparatus for an internal combustion engine of the present invention, a DC / DC converter is provided on an electric circuit between the battery and the valve control means, and the battery voltage detected by the battery voltage detection means when a specific condition is satisfied is equal to or less than a threshold value. In this case, the voltage supplied from the battery to the valve control means may be boosted by the DC / DC converter.

  In this internal combustion engine control device, when a specific condition for performing cylinder deactivation operation is satisfied and the battery voltage detected by the battery voltage detecting means is equal to or lower than the threshold value, the battery voltage lowered by the DC / DC converter is boosted and the boosted voltage is increased. The valve control means is energized with the determined voltage. By this control, the decrease in the battery voltage is compensated by boosting by the DC / DC converter, and the energization to the valve control means is performed in the same manner as when the battery voltage is normal. As a result, it is possible to suppress a time delay from the start of the control for maintaining the intake valve and / or the exhaust valve to the closed state. Thus, in this internal combustion engine control apparatus, the reduced battery voltage is boosted and the valve control means is energized, whereby the timing at which the intake valve and / or the exhaust valve are closed and the timing at which fuel injection is stopped. As much as possible, oxygen can be prevented from flowing into the catalyst as much as possible.

  In the control apparatus for an internal combustion engine according to the present invention, when the battery voltage detected by the battery voltage detection means when the specific condition is satisfied is less than or equal to the threshold value, the DC / DC converter increases the difference between the threshold value and the battery voltage. It is preferable to increase the degree of boosting the voltage supplied from the battery to the valve control means.

  In this control apparatus for an internal combustion engine, when a specific condition for performing cylinder deactivation operation is satisfied and the battery voltage is equal to or lower than the threshold value, the battery voltage lowered by the DC / DC converter is boosted as the difference between the threshold value and the battery voltage increases. Increase the degree. Thus, in this control device for an internal combustion engine, the control for maintaining the closed state of the intake valve and / or the exhaust valve is started by increasing the degree of pressure increase as the difference between the threshold value and the battery voltage increases. The time delay from when the valve is closed to when the valve is closed can be minimized.

  The present invention can suppress the deterioration of the catalyst by delaying the timing of stopping the fuel injection when the battery voltage is lowered during the cylinder deactivation operation.

It is a block diagram of an engine control device (cylinder deactivation function) and a boost control device according to the present embodiment. It is an example of the time change of the solenoid current at the time of electricity supply to the solenoid drive power supply from the battery of FIG. It is a flowchart which shows the flow of a process in engine control ECU of FIG.

  Embodiments of a control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the control device for an internal combustion engine according to the present invention is applied to an engine control device for a vehicle equipped with a 4-cylinder gasoline engine. A catalyst device composed of a three-way catalyst is disposed in the exhaust passage of the gasoline engine according to the present embodiment. Further, the vehicle according to the present embodiment is equipped with a boost control device for boosting the battery voltage when the battery voltage is lowered. The engine control apparatus according to the present embodiment has a cylinder deactivation function, and deactivates some or all of the four cylinders during low-load operation or idling.

  With reference to FIG.1 and FIG.2, the engine control apparatus 1 which concerns on this Embodiment is demonstrated. FIG. 1 is a configuration diagram of an engine control device (cylinder deactivation function) and a boost control device according to the present embodiment. FIG. 2 is an example of a temporal change in solenoid current when the solenoid power supply from the battery of FIG. 1 is energized.

  In the cylinder deactivation function of the engine control device 1, when performing the cylinder deactivation control, control is performed to suppress deterioration of the three-way catalyst of the catalyst device when the battery voltage is low. In this control, it is determined whether or not an emergency fuel cut occurs. If the fuel cut is not an emergency fuel cut, the fuel cut is delayed by one cycle. If the fuel cut is an emergency fuel cut, the battery voltage is increased.

  Note that emergency fuel cut (emergency cylinder deactivation) stops the engine (cylinder) urgently, such as when engine parts such as ignition, injection, and intake / exhaust valves fail, or when the engine overruns (excessively high rotation). This is a fuel cut (cylinder deactivation) when necessary. Since it is necessary to perform an emergency fuel cut when the engine is abnormal, it is necessary to immediately stop fuel injection and stop the cylinder.

The configuration required cylinder deactivation function in the engine control device 1, a battery voltage sensor 10, a crank angle sensor 11, an accelerator opening sensor 12, the first to fourth cylinder intake solenoid ₂₀ I1 _{to 20 I4,} first to fourth cylinder exhaust solenoid ₂₀ E1 _{to 20 E4,} the first to fourth injectors ₂₁ 1 to 21 ₄ and the engine control ECU [Electronic control Unit] 30 (fuel cut request-valve stop request processing 31a, solenoid driving processing 31b, the fuel-cut treatment 31c , A boost voltage determination process 31d) is provided, and the boost control device 2 is used.

  In the present embodiment, the battery voltage sensor 10 corresponds to the battery voltage detection means described in the claims, and the solenoid 20 (including the solenoid drive power source 20a) and the solenoid drive processing 31b are in the claims. The injector 21 and the fuel cut process 31c correspond to the fuel injection control means described in the claims.

  The battery voltage sensor 10 is a sensor that detects the voltage of the battery 22. The battery voltage sensor 10 detects the battery voltage and transmits the detected value to the engine control ECU 30.

  The crank angle sensor 11 is a sensor that detects the rotation angle (crank angle) of the crankshaft of the engine. The crank angle sensor 11 detects the crank angle and transmits the detected value to the engine control ECU 30.

  The accelerator opening sensor 12 is a sensor that detects the amount of depression of the accelerator pedal (accelerator opening) by the driver. The accelerator opening sensor 12 detects the accelerator opening and transmits the detected value to the engine control ECU 30.

The first to fourth cylinder intake solenoids 20 _{I1 to} 20 _I4 are solenoids for controlling the opening and closing of the intake valves of the respective cylinders. The intake solenoids 20 _{I1 to} 20 _I4 of each cylinder are energized from the battery 22 to the solenoid driving power source 20 a in response to a command from the engine control ECU 30, and are energized from the solenoid driving power source 20 a to the intake solenoid 20 _{I of} each cylinder. Open and close the intake valve accordingly.

The first to fourth cylinder exhaust solenoids 20 _{E1 to} 20 _E4 are solenoids for controlling the opening and closing of the exhaust valves of the respective cylinders. First to fourth cylinder exhaust solenoid ₂₀ E1 _{to 20 E4} is because they are similar to the first to fourth cylinders of the intake solenoid ₂₀ I1 _{to 20 I4,} the description thereof is omitted.

  The solenoid driving power source 20 a is a capacitor and is energized from the battery 22 via the DC / DC converter 23. While the holding current is maintained by energizing the solenoid driving power source 20a, the valve can be maintained closed by the action of the solenoid 20.

  As shown in FIG. 2, when the voltage of the battery 22 is normal (12V), it is held in the solenoid driving power source 20a as shown by the time change of the current supplied from the battery 22 to the solenoid driving power source 20a by the solid line C1. The time required until electric current is supplied (and thus from the valve stop request to the completion of valve stop) is a predetermined time α within one cycle of the engine (two rotations of the crankshaft [720 crank angle]). Therefore, from the valve stop request to the valve stop completion is within one cycle of the engine. However, when the voltage of the battery 22 decreases (for example, about 10 V), the time required for the holding current to be supplied to the solenoid driving power source 20a as shown by the broken line C2 is the predetermined time α. The time γ is longer, and the current supplied from the battery 22 rises (responsiveness) later than normal. Therefore, from the valve stop request to the valve stop completion exceeds one cycle of the engine, it is necessary to assume two cycles with a margin.

First to fourth injectors ₂₁ 1 to 21 ₄ is a device that injects fuel into an intake manifold or cylinder of each cylinder. The injector 21 ₁ to 21 ₄ of each cylinder, to stop the injection or or injection of fuel a predetermined amount of fuel in response to a command from the engine control ECU 30.

  The engine control ECU 30 is an electronic control unit including a CPU [Central Processing Unit] 31 and various memories, and performs overall control of the engine control apparatus 1. The engine control ECU 30 executes a fuel cut request / valve stop request process 31a, a solenoid drive process 31b, a fuel cut process 31c, and a boost voltage determination process 31d by executing various application programs related to the cylinder deactivation function by the CPU 31.

  The fuel cut request / valve stop request process 31a will be described. In the fuel cut request / valve stop request processing 31a, a low load operation state, an idling state, etc. of the vehicle are determined based on the crank angle detected by the crank angle sensor 11 and the accelerator opening detected by the accelerator opening sensor 12, and the cylinder is determined. It is determined whether to execute the pause control. If it is determined that the cylinder deactivation control is to be executed during normal operation, the fuel cut request / valve stop request process 31a sets a combination of cylinders to be deactivated, and issues a fuel cut request including information on the combination of cylinders to be deactivated. While outputting to the fuel cut process 31c, a valve stop request | requirement is output to the solenoid drive process 31b. When it is determined that the cylinder deactivation control is to be terminated during the cylinder deactivation operation, in the fuel cut request / valve stop request process 31a, the fuel cut end request is output to the fuel cut process 31c, and the valve stop end request is transmitted to the solenoid drive process 31b. Output.

  Various conventional methods can be applied as this determination method. For example, it is determined that the accelerator is OFF based on the detected value of the accelerator opening during normal operation (there is no acceleration request from the driver) and the detected value of the crank angle If the engine speed is determined to be equal to or higher than the predetermined engine speed (the engine is not in a low speed state), it is determined that the cylinder deactivation control is to be executed, and the accelerator ON (driver If it is determined that there is a request for acceleration), it is determined that the cylinder deactivation control has ended.

  Further, when it is determined by the failure determination function of the engine control ECU 30 that an emergency fuel cut (emergency cylinder deactivation) at the time of abnormality needs to be performed, in the fuel cut request / valve stop request processing 31a, information indicating an emergency Is output to the fuel cut process 31c, and a valve stop request is output to the solenoid drive process 31b.

The solenoid driving process 31b will be described. In the solenoid drive process 31b, when a valve stop request is output from the fuel cut request / valve stop request process 31a, the battery 22 is energized to supply a holding current to the solenoid drive power supply 20a, and the solenoid drive power supply 20a energized intake solenoid 20 _I of each cylinder pausing the exhaust solenoid 20 _E, close the exhaust valves by an exhaust solenoid 20 _E closes the intake valve by the intake solenoid 20 _I (valve stop). Further, the solenoid driving processing 31b, the fuel if the cut request-valve stop request processing 31a valve stop termination request from has been outputted, quiescent for each cylinder was also the intake solenoid 20 _I and the exhaust solenoid 20 normal energization control to _E It was carried out, to open and close control of the exhaust valves by an exhaust solenoid 20 _E as well as controls the opening and closing of the intake valve by the intake solenoid 20 _I. In the solenoid drive process 31b, the valve stop control is immediately executed when a valve stop request is issued regardless of whether the battery voltage is normal or decreased.

  The fuel cut process 31c will be described. In the fuel cut process 31c, when a fuel cut request is output from the fuel cut request / valve stop request process 31a, it is determined whether or not the battery voltage detected by the battery voltage sensor 10 is equal to or lower than a threshold voltage. This threshold voltage is a threshold value for determining a decrease in battery voltage that is worse than when the rise (responsiveness) of the current supplied to the solenoid driving power source 20a is normal, and depends on the engine speed, solenoid temperature, etc. It is a variable value. When the battery voltage is higher than the threshold voltage, in the fuel cut process 31c, when there is a fuel cut request, a stop command is output to the injector 21 of each cylinder that is immediately stopped to stop fuel injection (fuel cut). When the stop command is issued immediately in this way, the fuel injection is stopped at the next fuel injection timing in the cylinder to be stopped (the fuel injection stop is completed within one cycle from the fuel cut request). In this case, the valve stop is also completed within one cycle from the valve stop request.

  When the battery voltage is equal to or lower than the threshold voltage, the fuel cut process 31c determines whether or not the fuel cut is an urgent fuel cut based on information included in the fuel cut request. If it is not an urgent fuel cut, in the fuel cut process 31c, after one cycle of the engine has elapsed from the fuel cut request, a stop command is output to the injector 21 of each cylinder to be stopped to stop fuel injection. When a stop command is issued with a delay of one cycle in this way, the fuel is injected at the timing of injecting the next fuel in the cylinder to be stopped, and is stopped from the fuel injection at the timing of the next injection of fuel (fuel). The fuel injection stop is completed within one cycle after one cycle has elapsed from the cut request). In this case, the valve stop is completed within two cycles from the valve stop request.

  On the other hand, in the case of emergency fuel cut, in the fuel cut process 31c, when there is a fuel cut request, the boost voltage determination command is immediately output to the boost voltage determination process 31d, and the stop command is output to the injector 21 of each cylinder to be stopped. Then, the fuel injection is stopped. When the stop command is issued immediately in this way, the fuel injection stop is completed within one cycle from the fuel cut request as described above. In this case, the voltage of the battery 22 is lower than normal, but since the battery voltage is boosted and energized to the solenoid driving power supply 20a, the valve stop is also completed within one cycle from the valve stop request. .

  The boosted voltage determination process 31d will be described. In the boost voltage determination process 31d, when the boost voltage determination command is output from the fuel cut process 31c, the current battery voltage detected by the battery voltage sensor 10 from the normal battery voltage (for example, 12V) (the normal battery voltage) Lower voltage), and a voltage difference obtained by the subtraction is used as a boosted voltage. Therefore, the boosted voltage increases as the battery voltage decreases. In the boost voltage determination process 31d, a boost command including information on the boost voltage is transmitted to the boost control ECU 40.

  The boost control device 2 will be described. The boost control device 2 is a device that boosts the voltage of the battery 22. The boost control device 2 includes a DC / DC converter 23 and a boost control ECU 40 (boost control process 41a).

  The DC / DC converter 23 is a voltage converter that is connected to the battery 22 and converts the battery voltage (DC input voltage) into a DC output voltage having a predetermined voltage value. The DC / DC converter 23 boosts the battery voltage in accordance with control from the boost control ECU 40, and energizes the solenoid driving power source 20a with the boosted voltage.

  The step-up control ECU 40 is an electronic control unit including a CPU 41 and various memories, and performs overall control of the step-up control device 2. The step-up control ECU 40 executes the step-up control process 41a by executing an application program related to the step-up control function on the CPU 41. In the boost control process 41a, when a boost command is received from the engine control ECU 30, the DC / DC converter 23 is controlled to boost the battery voltage by the boost voltage included in the boost command.

  The operation of the cylinder deactivation function in the engine control device 1 will be described with reference to FIG. In particular, the process of the cylinder deactivation function in the engine control ECU 30 will be described along the flowchart of FIG. FIG. 3 is a flowchart showing a flow of processing in the engine control ECU of FIG. The engine control ECU 30 repeats the process of FIG.

  The battery voltage sensor 10 detects the voltage of the battery 22 at regular intervals and transmits the detected value to the engine control ECU 30. The crank angle sensor 11 detects the crank angle at regular intervals and transmits the detected value to the engine control ECU 30. The accelerator opening sensor 12 detects the accelerator opening at regular intervals, and transmits the detected value to the engine control ECU 30.

  The engine control ECU 30 performs a fuel cut and valve stop execution (cylinder deactivation control execution) determination process based on the crank angle and the accelerator opening (S1), and outputs a fuel cut request and a valve stop request when it is determined to execute. (S2). If the fuel cut request and the valve stop request are not output in S2, the engine control ECU 30 ends the current process. When it is determined that an urgent fuel cut (cylinder deactivation) is necessary for an abnormality in the engine, the engine control ECU 30 outputs a fuel cut request and a valve stop request including the urgent information (S2).

When the fuel cut request and the valve stop request are output in S2, the engine control ECU 30 compares the voltage of the battery 22 with the threshold voltage to determine whether the battery voltage is decreasing (S3). If the battery voltage at S3 is determined not to be reduced, the engine control ECU 30, immediately, the energization control to respect the intake solenoid 20 _I of each cylinder pausing closed intake valve and to an exhaust solenoid 20 _E The energization is controlled to close the exhaust valve (S4), and the injector 21 is controlled to stop fuel injection (S5).

  If it is determined in S3 that the battery voltage is decreasing, the engine control ECU 30 determines whether or not an emergency fuel cut is made based on information included in the fuel cut request (S6).

If the emergency fuel cut is determined in S6, the engine control ECU 30 immediately determines the boost voltage based on the current lowered battery voltage (S7), and sends a boost command including information on the boost voltage to the boost control device. 2 (step-up control ECU 40) (S8). When this boost command is received, the boost control ECU 40 controls the DC / DC converter 23 to boost the battery voltage. The DC / DC converter 23 boosts the battery voltage. Further, the engine control ECU 30, immediately, the energization control to respect the intake solenoid 20 _I of each cylinder pausing closing the intake valves and the energization control to closes the exhaust valve against the exhaust solenoid 20 _E (S9) Then, the injector 21 is controlled to stop fuel injection (S10). At this time, the fuel injection by the injector 21 is stopped within one cycle from the fuel cut request. Further, since the solenoid driving power source 20a is energized with a voltage boosted from the battery voltage that has decreased, the holding current is supplied to the solenoid driving power source 20a within one cycle from the valve stop request. The exhaust valve is fully closed. Therefore, oxygen is not exhausted and oxygen does not flow into the three-way catalyst of the catalyst device.

If it is determined not to be an emergency fuel cut at S6, the engine control ECU 30, immediately, the energization control to respect the intake solenoid 20 _I of each cylinder pausing closing the intake valves and the energization control with respect to the exhaust solenoid 20 _E Then, the exhaust valve is closed (S11). Further, the engine control ECU 30 determines whether or not one cycle has elapsed from the fuel cut request (S12) and waits until one cycle has elapsed. If it is determined in S12 that one cycle has elapsed, the engine control ECU 30 controls the injector 21 to stop fuel injection (S13). At this time, since the battery voltage is lowered, it takes more time than normal when the holding current is supplied to the solenoid driving power source 20a, and within two cycles from the valve stop request, the solenoid driving power source 20a Is supplied with a holding current, and the intake valve and the exhaust valve are fully closed. Further, the fuel is injected from the injector 21 for one cycle from the fuel cut request, and the fuel injection by the injector 21 is also stopped within the next one cycle after the elapse of one cycle. Therefore, in the first cycle, combustion is performed with the injected fuel, so that oxygen is not exhausted. In the next cycle, the valve is closed and oxygen is not exhausted, and oxygen does not flow into the three-way catalyst of the catalyst device.

  According to the engine control device 1, when the battery voltage is reduced during the cylinder deactivation operation, the deterioration of the catalyst can be suppressed by delaying the fuel cut timing. At this time, the completion of the valve stop is delayed due to a decrease in the battery voltage, but by delaying the fuel cut timing by one cycle, the valve stop and the fuel cut timing can be synchronized with each other with a delay of one cycle from the normal time. Oxygen can be prevented from flowing into the three-way catalyst.

  Further, according to the engine control device 1, when the battery voltage is reduced at the time of emergency fuel cut, the reduced battery voltage is boosted by the DC / DC converter 23 and energized to the solenoid driving power source 20a, thereby producing a catalyst. Can be prevented. At this time, the increase in the battery voltage is compensated for by boosting, energization of the solenoid driving power source 20a is performed in the same manner as when the battery voltage is normal, and the valve stop can be completed within one cycle from the valve stop request. The stop completion timing and the fuel cut timing can be matched, and oxygen can be prevented from flowing into the catalyst. Further, since fuel cut and valve stop can be executed without delay, it is possible to respond quickly to an engine abnormality.

  Further, in the engine control device 1, the boosted voltage is determined according to the difference between the battery voltage that has decreased during boosting and the normal battery voltage, thereby matching the valve stop completion timing and the fuel cut timing more accurately. It is possible to prevent oxygen from flowing into the catalyst as much as possible. At this time, although the actual battery voltage has dropped, the solenoid drive power supply 20a can be energized with a voltage comparable to the normal battery voltage, so that the valve is stopped at the same timing as normal from the valve stop request. Can be completed, and the valve stop completion timing and the fuel cut timing can be matched.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the present invention is applied to a four-cylinder gasoline engine vehicle. However, the number of cylinders can be applied to a vehicle having another cylinder number. The present invention can also be applied to a hybrid vehicle including an engine and a motor.

  In this embodiment, the present invention is applied when a three-way catalyst is used as a catalyst. However, the present invention can also be applied when another catalyst is used.

  In the present embodiment, the boost control device is provided separately from the engine control device. However, the boost control function may be configured in any manner, for example, the boost control function is provided in the engine control device. You may have.

  In the present embodiment, when the valve is stopped, both the intake valve and the exhaust valve are closed. However, only one of the valves may be closed.

  In the present embodiment, when the cylinder deactivation control is performed, if the battery voltage is equal to or lower than the threshold voltage, the fuel cut is delayed by one cycle (fixed value). However, the delay time is set to other than one cycle. Also good. For example, when the battery voltage is equal to or lower than the threshold voltage, the delay time is lengthened as the difference between the lowered battery voltage and the threshold voltage is larger (as the difference between the lowered battery voltage and the normal battery voltage is larger). By changing the time for delaying the fuel cut in this way, the timing of valve stop completion and the timing of fuel injection stop can be matched as much as possible, and oxygen can be prevented from flowing into the catalyst as much as possible.

  Further, in the present embodiment, when executing the cylinder deactivation control, it is determined whether or not the emergency fuel cut is performed when the battery voltage is equal to or lower than the threshold voltage, and the control for delaying the execution of the fuel cut by one cycle or boosting the battery voltage is performed. However, if the battery voltage is equal to or lower than the threshold voltage when the cylinder deactivation control is executed, the fuel cut is executed for one cycle without determining the emergency fuel cut. A configuration may be adopted in which one of the control for delaying and the control for boosting the battery voltage and immediately executing the fuel cut are performed.

  Further, even when the energization state of the solenoid driving power source is detected and the battery voltage is lowered, if the solenoid driving power source is already sufficiently energized (holding current is supplied), the fuel cut is executed for one cycle. The control similar to the case where the battery voltage is normal may be performed without performing the delay control or the control for immediately increasing the battery voltage and immediately executing the fuel cut.

  In addition, if the battery voltage is equal to or lower than the threshold voltage when performing cylinder deactivation control, it is necessary to delay the execution of fuel cut for each cylinder to be deactivated instead of delaying the execution of fuel cut for all cylinders to be deactivated. It may be determined whether or not fuel cut execution is delayed only for the cylinders that need to be delayed.

  In the valve stop energization control, the energization may be performed while controlling the energization amount by duty control or the like, and the time from the valve stop request to the valve stop completion may be adjusted.

1 ... engine control unit, 2 ... boost control device, 10 ... battery voltage sensor, 11 ... crank angle sensor, 12 ... accelerator opening _sensor, 20 I1 to 20 _{I4 ...} first to fourth cylinder intake _solenoid, 20 E1 to 20 _E4 ... 1st to 4th cylinder exhaust solenoid, 20a ... Solenoid drive power supply, 21 _{1 to} 21 ₄ ... 1st to 4th cylinder injector, 22 ... Battery, 23 ... DC / DC converter, 30 ... Engine control ECU, 31 ... CPU, 31a ... Fuel cut request / valve stop request process, 31b ... Solenoid drive process, 31c ... Fuel cut process, 31d ... Boost voltage determination process, 40 ... Boost control ECU, 41 ... CPU, 41a ... Boost control process.

Claims (4)

A control device for an internal combustion engine that also performs cylinder deactivation operation for deactivating a cylinder when a specific condition is satisfied,
Fuel injection control means for controlling fuel injection for each cylinder and stopping fuel injection when the specific condition is satisfied;
Valve control means for controlling the opening and closing of the intake valve and the exhaust valve for each cylinder, and holding and controlling the closed state of the intake valve and / or the exhaust valve when the specific condition is satisfied;
Battery voltage detection means for detecting the voltage of the battery,
The valve control means respectively controls the opening and closing of the intake valve and the exhaust valve for each cylinder by each solenoid according to the energization state from the battery, and holds and controls the closed state by each solenoid,
The control apparatus for an internal combustion engine, characterized in that the fuel injection control means delays the timing of stopping fuel injection when the battery voltage detected by the battery voltage detection means is not more than a threshold value when the specific condition is satisfied.   When the battery voltage detected by the battery voltage detection unit is less than or equal to a threshold value when the specific condition is satisfied, the fuel injection control unit stops the fuel injection as the difference between the threshold value and the battery voltage increases. 2. The control apparatus for an internal combustion engine according to claim 1, wherein the control is delayed. A DC / DC converter on an electric circuit between the battery and the valve control means;
When the battery voltage detected by the battery voltage detection means is less than a threshold value when the specific condition is satisfied, the voltage supplied from the battery to the valve control means is boosted by the DC / DC converter. The control apparatus for an internal combustion engine according to claim 1 or 2.   When the battery voltage detected by the battery voltage detection means when the specific condition is satisfied is less than or equal to a threshold value, the valve control is performed from the battery by the DC / DC converter as the difference between the threshold value and the battery voltage increases. 4. The control apparatus for an internal combustion engine according to claim 3, wherein the degree of boosting the voltage supplied to the means is increased.